The invention relates to apparatus for and methods of damage repair, more particularly but not exclusively in the field of repair of vehicle glass which is frequently chipped by flying stones or other material. The term xe2x80x9cflawxe2x80x9d used herein is to cover chips defects or other surface faults.
Existing apparatus and methods for repair of damaged vehicle glass involve subjecting a space around the area of damage to a partial vacuum to allow satisfactory penetration of an optically compatible resin into the area of damage, and extraction of air from the resin itself, curing the resin once the damaged area has been filled, and finishing the repair by removing excess cured resin and polishing the surface of the previously damaged area.
Problems which arise concern adequate degassing of both the damaged area and the resin. For example, the apparatus described in U.S. Pat. No. 4,419,3005 and U.S. Pat. No. 4,385,015 has a suction cup connected to a vacuum pump. A tube extends through the suction cup and seals against the surface of the glass around the flaw to be repaired. The inside of the tube communicates through a radial vacuum port with the space inside the suction cup. Resin is introduced into the tube and a piston is then introduced into the tube, at which time the vacuum pump acts on the flaw and the resin in the flaw to degas both the resin and the flaw. De-gasification in this way needs more time and is less effective, since gas from the flaw has to leave through the resin.
U.S. Pat. No. 4,776,780 describes a hand-operated suction cup through which a passage is provided for receiving repair liquid, such as a curable resin. The passage seals against the surface of the glass when a vacuum is applied to the suction cup, and the passage is completely isolated then from the suction cup interior. Resin is introduced into the passage and a piston is moved up and down in the passage to evacuate or pressurising the space within the passage. This apparatus encounters similar degassing problems described above.
According to one aspect of the invention, there is provided apparatus for repairing a flaw in a surface, which apparatus comprises:
housing adapted to engage the surface,
a repair seal for sealing between the housing and around the flaw to be repaired to define between the surface and the housing a repair space over the flaw,
a reservoir communicating with the repair space for containing liquid repair material,
vacuum means communicating with the repair space and the reservoir to apply a partial vacuum to the repair space and to the reservoir without repair liquid from the reservoir being drawn into the repair space in order to degas separately the flow and repair liquid in the reservoir, and means for causing repair liquid, in use, to flow from the reservoir into the repair space to fill the repair space with repair liquid.
The apparatus preferably includes means for exerting pressure on the repair space.
The invention further provides apparatus for repairing a flaw in a surface, which apparatus comprises:
a housing adapted to engage the surface,
a repair seal for sealing between the housing aid around the flaw to be repaired to define between the surface and the housing a repair space over the flaw, first vacuum means communicating with the repair space for applying a partial vacuum to the repair space, second vacuum means for applying an enhanced vacuum to the repair space, and
a reservoir for supplying repair liquid to the repair space.
The second vacuum means preferably comprises a piston slidably located in a bore in the housing, which bore communicates with the repair space.
The piston is preferably movable between a first position in which the partial vacuum applied by the vacuum means exists in the repair space and a second position in which the enhanced vacuum is applied to the repair space.
Valve means are preferably located in the housing between the first vacuum means and the second vacuum means such that when the second vacuum means is in use, the first vacuum means is isolated from the repair space.
The piston is preferably movable to a third position in which the bore and repair space are returned to external pressure, movement of the piston back towards the first position thereby exerting pressure on the repair space.
The piston positions are preferably defined by a cam extending from one of the piston and the bore wall, and a groove in the other of the piston and the bore wall to control piston travel within the bore.
The housing preferably includes an outer seal, the outer seal and the repair seal defining an annular space between the housing and the surface in use, the annular space having a connection to a vacuum source for reducing the pressure in the annular space to hold the housing to the surface in use.
The invention further provides a flexible patch for use with apparatus for repairing a flaw in a surface, which apparatus is of the type in which liquid repair material is introduced into a partly evacuated repair space adjacent the flaw, the patch being of gas and liquid impermeable sheet material and having a ring of adhesive on one side thereof for adhering to the surface around the flaw to be repaired, the patch including at least one slit therein within the ring of adhesive to allow liquid and gas to pass through the or each sit.
The patch preferably has two slits.
The adhesive ring is preferably of a thickness greater than 200 microns extending proud of the patch surface. A preferred adhesive ring thickness is 350 microns.
The invention further provides apparatus for repairing a flaw in a surface comprising a housing adapted to engage the surface, a repair seal for sealing between the housing and around the flaw to be repaired to define between the housing and the surface a repair space over the flaw, vacuum means communicating with the repair space for applying a partial vacuum to the repair space and a reservoir for supplying liquid repair material to the repair space, the reservoir comprising a capsule containing liquid repair material and a capsule holder in the housing, the capsule holder communicating with the repair space and including a release element for releasing liquid repair material from the capsule into the capsule holder when the capsule is inserted into the capsule holder.
The capsule is preferably cylindrical and includes an annular seal extending around the cylindrical outer surface thereof intermediate the ends of the capsule to form a seal with the interior surface of the capsule holder in the housing.
The capsule preferably includes an internal membrane to retain liquid repair material in the capsule, and the release element is preferably a spike to break the membrane when the capsule is inserted in the capsule holder.
When the liquid repair material is first released from the capsule into the capsule holder, the volume of the capsule holder is preferably sufficient to contain the liquid repair material without any liquid repair material reaching the repair space.
Upon full insertion of the capsule into the capsule holder, the repair space is preferably filled with liquid repair material.
The apparatus preferably includes a capsule position locating element on the housing for locating the capsule in a first position in which the liquid repair material is released and retained in the capsule holder or a second position in which the capsule is retained in a fully inserted position. The capsule preferably has a flange at the end thereof away from the end for insertion with the capsule holder, and the capsule position locating element is preferably an element spring biased to engage the flange to prevent movement of the capsule beyond the first position until moved inwardly, and engageable with the flange to prevent removal of the capsule when fully inserted, until moved inwardly towards the housing.
The invention further provides a method of repairing a flaw in a surface comprising the steps of forming a repair space adjacent the flaw;
applying a vacuum to the repair space and to liquid repair material while the liquid repair material is held outside the repair space;
introducing the liquid repair material into the repair space;
removing the vacuum applied to the repair space and then pressurising the repair space;
removing the repair space;
curing the liquid repair material until hard, and smoothing the repaired surface.
There is preferably an initial step of securing a patch over the flaw, the patch having a ring of adhesive surrounding the flaw, before forming the repair space, the patch being removed after curing the liquid repair material.